The inhibition and activation of polyamine oxidase from oat seedlings

Abstract

In a homologous series of di-guanidines (NH2C(= NH)NH(CH2)xNHC(= NH) NH2) where x = 2-12, greatest inhibition of polyamine oxidase was found with x : 8. The synthetic fungicide guazatine NH2C(= NH)NH --(CH ~)s,....~ N H NH2C(= NH)NH --(CH2)8 /was particularly effective as an inhibitor of polyamine oxidase, with Ki of ca 10-~ M. Inhibition due to the tri-amine derived from guazatine by hydrolysis was less effective by a factor of ca 200. Comparison of various inorganic salts at I Mshowed that polyamine oxidase activity was enhanced in the order RbC1 > KCI > KBr > NH,CI > NaNO 3 > LiCI = NaC1 > control (no salt) > CaC12 = MgCI~. Activity in RbC1 was about 4 to 5 times greater than in the salt-free control. Enzyme activity is rapidly lost during assay. This loss of activity could not be attributed to inhibition by aminopropylpyrroline or diaminopropane. Moreover the superoxide scavenger copper salicylate had no protective effect on enzyme activity.

Effect of polyamines on stabilization of molecular complexes in thylakoid membranes of osmotically stressed oat leaves

“…Added polyamines which are rapidly converted by the leaf tissue to Dap may inhibit polyamineoxidase activity, the main catabolic route for polyamines in cereals, resulting in less degradation of endogenous Spd and Spm. Recent experiments with guazatine, an inhibitor of polyamine-oxidase activity (Smith 1985), show that it is possible to reduce the Dap content with a concomitant increase of Spd and Spm levels, and this is correlated with a prevention of osmotically induced chlorophyll loss (Capell et al 1992). This finding adds further support to the hypothesis that polyamines are directly involved in preventing degradation of the chlorophyll-protein complexes during osmotic stress.…”

Guanylated Diamines, Triamines, and Polyamines: Chemistry and Biological Properties

“…Data are reported in Table . The optimum length for alkylic chain of biguanylated triamines is C = 8, while the most active compound proved to be 365c bearing a cyclopropylmethyl moiety bound to one of the guanidine portion . Monoguanylated diamines 127 were also tested showing ZmPAO inhibitory activity in the mM range.…”

Polyamine Induction in Postharvest Banana Fruits in Response to NO Donor SNP Occurs via l-Arginine Mediated Pathway and Not via Competitive Diversion of S-Adenosyl-l-Methionine

“…PAs are positively charged at physiological pH and hence they tend to bind strongly with negatively charged nucleic acids [19], acidic phospholipids and various types of proteins [20]. It is well known that supplementation of PAs provides anti-senescence effects in many plant species [21]. Such effects have obviously relevant in the context of fruit ripening since ripening is a senescence phenomenon [22].…”